Drum brake assemblies, particularly of the non-servo type, provide for a pair of brake shoes arranged in end-to-end relationship supported on a backing plate that is interconnected with a stationary part of the vehicle. A hydraulic actuator is disposed between two ends of the brake shoes, receiving the brake shoe webs; while an anchor assembly is disposed adjacent the other two ends of the brake shoes opposite the hydraulic actuator. The anchor assembly receives and transmits forces from the liningdrum boundary, through the backing plate, to a stationary part of the vehicle, such as the vehicle axle flange. The anchor assembly may also include a retainer assembly for retaining portions of the brake shoes, particularly the brake shoe webs, in engagement with an anchor bearing surface and in axial alignment therewith.
Anchor assemblies, such as those illustrated in U.S. Pat. Nos. 4,101,011 and 3,283,858, include an anchor block providing bearing surfaces for engaging the brake shoe webs, a separate retainer or guide plate overlying the anchor block, and a pair of rivets extending through both of such members for securing the assembly to the backing plate. Such assemblies are costly to manufacture and to assemble, requiring an inordinate number of parts. Moreover, such assemblies require a solid block of material serving as the bearing or anchor plate, thus increasing the overall weight of the brake assembly. In addition, forces transmitted from the brake shoes to the backing plate are taken up by the rivets, thus localizing the high forces that may occur.
Anchor assemblies, such as those illustrated in U.S. Pat. No. 2,509,643, provide for an anchor block for receiving the brake shoe webs and having retaining projections unitary with the block overlying the brake shoe webs. The anchor block is spot welded directly onto the backing plate. Nibs on the anchor block mate with openings in the backing plate to take up the braking forces. Such assemblies are costly to manufacture and fail to avoid high stress buildup localized at the nib-opening interface.
Anchor assemblies, such as those illustrated in U.S. Pat. Nos. 2,942,696, and 3,351,159, provide for portions of the brake shoe webs to directly contact raised portions of the backing plate. Since backing plates are generally of relatively soft metal, deformities in the backing plate can occur. Alternatively, the backing plate must be reinforced at the bearing area, resulting in undesirable increases in overall weight of the brake assembly.